Crow, whose hits include 'If It Makes You Happy', dated the cyclist between 2003 and 2006 and was engaged to marry him before they split. According to the Daily News, she was quizzed by officials late last year as part of a two-year investigation into Armstrong and his teammates.
Armstrong has always denied any wrongdoing but was last week stripped of his seven Tour de France titles by the United States Anti-Doping Agency after deciding not to contest charges against him.
Speaking in a 2005 interview, Crow dismissed the allegations that have plagued Armstrong's career as "a nuisance".
"I don't think the French people are on a mission to strip him of his integrity," she said. "It's just a handful of people pursuing that theory, and it's tiresome and a nuisance, and it will eventually end, I hope."
Armstrong has urged fans "not to cry" for him in the wake of his punishment.